Long-term data on military compensation?

I'm looking for a study of trends in military compensation costs. There is a lot of discussion about privatization of military roles and often the reason given is that it costs so much to compensate an active soldier. By compensation, I don't mean pay alone, but all of the other expenditures (healthcare, housing, MWR, etc) that go into attracting and retaining military members and how that figure has changed over time. I'm primarily interested in the U.S., but if there are studies out there that include other major states that would be a bonus.